1. Industrial Utilization Field
The present invention relates to a bulletin device for indication or decoration in station yards, underground passages, buildings, exhibitions, etc. and more particularly to a device capable of freely adjusting the degree of stretching of a thin film- or sheet-like flexible bulletin and also capable of performing the mounting and replacement of such bulletin rapidly and easily in a suspended and stretched state to desired degree of tension.
2. Prior Art
For example, reference is here made to the bulletin device proposed in Japanese Utility Model Publication No. 25113/77 by the present inventor (see FIG. 12).
According to the construction of this proposed bulletin device, a pair of front and rear retaining receptacles 51 are formed inside a device frame 50, and a hook plate 52 is retained by the retaining receptacles 51 removably. A large number of hooks 53 are formed and arranged suitably on the surface of the plate 52, and springs 55 from which is suspended a bulletin 54 are suspended from the hooks 53.
Even in the cases of bulletins 54 having holes 56 for engagement with the springs 55 in different numbers and positions, each bulletin 54 can be suspended in a well-balanced stretched state by suspending the springs 55 from nearby hooks 53. Replacement of the bulletin 54 can be done easily by opening a parting piece 57 and disengaging the hook plate 52 with the springs 55 suspended therefrom from the front side of the device frame 50.
In the bulletin device of the above construction there are used a large number of springs for suspending the bulletin without looseness. But for adjusting the degree of stretching of the bulletin it is absolutely necessary to either increase or decrease the number of springs or make replacement with a spring having a desired pulling force. Besides, the spring mounting and removing operations are time-consuming troublesome operations because such springs are handled one by one.
Further, since the retaining receptacles of the hook plate are hidden by the rear side of the engaging portion which supports the parting piece for opening and closing motion, the hook plate mounting and removing operations are performed by groping for the retaining receptacles which are hidden by the rear side of the engaging portion and so not seen. Thus, the working efficiency is poor.